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Convergence insufficiency or Convergence Disorder is a sensory and neuromuscular anomaly of the binocular vision system, characterized by an inability of the eyes to turn towards each other, or sustain convergence.

Diagnosis

Diagnosis of convergence insufficiency is made by an eye care professional skilled in binocular vision dysfunctions to rule out any organic disease. Convergence insufficiency characterized by one or more of the following diagnostic findings: Patient symptoms, High exophoria at near, reduced accommodative convergence/accommodation ratio, receded near point of convergence, low fusional vergence ranges and/or facility. Some patients with convergence insufficiency have concurrent accommodative insufficiency -- accommodative amplitudes should therefore also be measured in symptomatic patients.

Treatment

Convergence insufficiency may be treated with convergence exercises prescribed by an eyecare specialist trained in orthoptics or binocular vision anomalies. Some cases of convergence insufficiency are successfully managed by prescription of eyeglasses, sometimes with therapeutic prisms.

In 2005, the Convergence Insufficiency Treatment Trial (CITT) published two randomized clinical studies. The first, published in Archives of Ophthalmology demonstrated that computer exercises when combined with in-office based vision therapy was more effective than "pencil pushups" or computer exercises alone for convergency insufficiency in 9 to 18 year old children.[1] The second found similar results for adults 19 to 30 years of age.[2]

Surgical correction options are also available, but the decision to proceed with surgery should be made with caution.

Bilateral medial rectus resection is usually the most effective operation for convergence insufficiency. However, the patient should be warned about the possibility of uncrossed diplopia at distance fixation after surgery. This typically resolves within 1-3 months postoperatively. The exophoria at near often recurs after several years, although most patients remain asymptomatic.

Prevalence

A British survey found that less than 1 in 300 patients receiving optometric eye examinations had convergence insufficiency[3] and a Spanish study found that nearly 1 in 100 (0.8%) of symptomatic patients in an optometric clinic had CI.[4] In contrast, studies conducted by the Southern California College of Optometry found that approximately 1 in 8 (13%) of fifth and six grade children examined during visual screenings had the disorder[5] as did nearly 1 in 5 (17.6%) of 8 to 12 year olds receiving examinations at optometry clinics.[6] A recent Romanian study revealed that roughly 3 in 5 (60.4%) of young adult patients complaining of blurred vision at near work suffered from convergence insufficiency.[7]

Optometry and vision science : official publication of the American Academy of Optometry.Optom Vis Sci.2011 Nov;88(11):1343-1352.

PURPOSE.: To report the effectiveness of various forms of vision therapy/orthoptics in improving accommodative amplitude and facility in children with symptomatic convergence insufficiency (CI) and co-existing accommodative dysfunction. METHODS.: In a randomized clinical trial, 221 children aged 9 t

OBJECTIVE: The purpose of this study is to investigate whether children with congenital esotropia (CET) are more likely than controls to develop mental illness by early adulthood.DESIGN: Retrospective, population-based cohort.PARTICIPANTS: Children (aged <19 years) diagnosed with CET while residi